This invention relates to an improved adjustable open-end wrench and more particularly to a simplified mechanism for one-hand adjustment of the wrench size.
Conventional adjustable open-end wrenches generally comprise a base jaw member, which is connected to a handle, and a movable jaw which is mounted upon the base jaw member. Various types of mechanisms have been provided for adjusting the location of the movable jaw member towards and away from the base jaw member and for maintaining it in position after the required distance between the grip portions of the jaw members is selected. One common way of adjusting the position of the movable jaw member is by means of a manually turned screw which moves the movable jaw towards or away from the base jaw member. This type of screw mechanism requires some time and care for properly adjusting the gap between the wrench base and movable jaw grip portions. Frequently, the grips are initially placed too close together or too far apart for a particular size bolt head or nut and, therefore, further careful adjustment is required.
In another type of adjustable open-end wrench mechanism, the movable jaw member is slidably mounted upon the base or fixed jaw member and is fixed in position by a ratchet or interengaging tooth system. This is illustrated in U.S. Pat. No. 1,434,753 issued Nov. 7, 1922 to Shackford.
Since open-end wrenches are susceptible to corrosion, their movable parts, particularly their adjustment mechanisms, tend to jam when corroded. Consequently, unless such wrenches are kept free of corrosion, they frequently become unusable when they have not been used for some while.
Further, prior open-end, adjustable-type wrenches are relatively complex in construction so that they are relatively expensive considering their purpose. Also, since they usually include a number of complex movable parts, they can be easily damaged.
Summarizing, there has been a need for a simply constructed, one-hand operated adjustable wrench which has virtually no moving parts and which will operate without difficulty, notwithstanding corrosion or dirt accumulations, and which is inexpensive to manufacture. The wrench of this present invention fills that need.